Methane emission from Canadian prairie and forest soils under short term flooding conditions

Abstract

Short term flooding of usually well-drained soils is a recurrent phenomenon in many regions of the world, particularly after snowmelt in the spring and after heavy and prolonged precipitation. Using incubation-leaching and static chamber techniques, we examined the impact of short term flooding on methane emission from Canadian prairie and forest soils. The laboratory study demonstrated that flooding caused significant methane evolution from incubated soils (13 to 184 mg kg^-1 over 8 weeks). In contrast, 80–95% of the atmospheric methane in the incubation jar was absorbed by nonflooded soils in a week. The field data showed that after snowmelt in the spring, the methane emission rate was highest in soils and ranged from 7.8 (cultivated) to 10.5 mg m^-2 d^-1 (grassland). Methane emission was also observed from low slope positions after rainfall in the summer. Three days after 23 mm of precipitation, the rate of methane evolution was 0.03 (cultivated) and 0.02 mg m^-2 d^-1 (grassland) whereas it was 0.11 (cultivated) and 0.07 mg m^-2 d^-1 (grassland) one day after 48 mm of precipitation.